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4952878 Magnetic resonance apparatus having an improved RF coil
XXVII
New Patents
bromide and at least 0.1% perfluorocarbon hydride are disclosed for intravascular use as a contrast agent or for oxygen transport.
4951675 BIODEGRADABLE SUPERPARAMAGNETIC METAL OXIDES AS CONTRAST AGENTS FOR MR IMAGING Ernest Groman, Lee Josephson, assigned to Advanced Magnetics
Jerome Lewis Incorporated
This invention relates to materials exhibiting certain magnetic and biological properties which make them uniquely suitable for use as magnetic resonance imaging (MRI) agents to enhance MR images of animal organs and tissues. More particularly, the invention relates to the in vivo use of biologically degradable and metabolizable superparamagnetic metal oxides as MR contrast agents. Depending on their preparation, these metal oxides are in the form of superparamagnetic particle dispersoids or superparamagnetic fluids where the suspending medium is a physiologically-acceptable carrier, and may be uncoated or surrounded by a polymeric coating to which biological molecules can be attached. These materials are administered to animals, including humans, by a variety of routes and the metal oxides therein collect in specific target organs to be imaged; in the case of coated particles, the biological molecules can be chosen to target specific organs or tissues. The biodistribution of the metal oxides in target organs or tissues results in a more detailed image of such organs or tissues because the metal oxides, due to their superparamagnetic properties, exert profound effects on the hydrogen nuclei responsible for the MR image. In addition, the dispersoids and fluids are quite stable and, in the case of the fluids, can even be subjected to autoclaving without impairing their utility. Furthermore, the materials are biodegradable and, in the case of iron oxide compounds, can eventually be incorporated into the subject’s hemoglobin, making them useful in treating anemia. Thus, the materials are well-suited for in vivo use.
A multiecho NMR pulse sequence is modified such that the bandwidth of the encoded NMR echo signal is reduced for the second NMR echo signal. This reduction is achieved by reducing the magnitude of the read-out magnetic field gradient, increasing the duration of the acquisition by a proportional amount and decreasing the sample rate by a proportional amount for the second NMR echo signal.
4952877 RF SYNTHESIZER OR AN NMR INSTRUMENT Robert S Stormont, Jeffrey P Noonan, Norbert Pelt assigned to General Electric Company The transceiver of an NRM instrument includes a digital synthesizer that produces an analog carrier signal which can be controlled in both frequency and phase and which can be frequency and phase modulated. The analog carrier signal is mixed with reference signals to boost its frequency to the Larmor frequency of the instrument.
4952878 MAGNETIC RESONANCE APPARATUS HAVING AN IMPROVED RF COIL Wilhelmus R M Mens, Peter H Wardenier, Eindhoven, Netherlands assigned to U S Philips Corporation An r.f. transmitter coil is coupled to individually or group-wise independently drivable antenna wire elements, each independently drivable element being driven by its own power amplifier via a sliding contact. An r.f. supply source is coupled to the inputs of the power amplifiers via an input network which provides a phase distribution among the r.f. signals supplied to the amplifiers for the coil to transmit with a circularly polarized r.f. field.
4952879 4952876 VARIABLE MULTIECHO Norbert J Pelt Company
BANDWIDTH NMR IMAGING
assigned
to General
Electric
MAGNETIC RESONANCE APPARATUS WITH UNCOUPLED RF COILS Johannes J Van Vaals, Anthonie Bergman, Eindhoven, Netherlands assigned to U S Philips Corporation
New Patents
bromide and at least 0.1% perfluorocarbon hydride are disclosed for intravascular use as a contrast agent or for oxygen transport.
4951675 BIODEGRADABLE SUPERPARAMAGNETIC METAL OXIDES AS CONTRAST AGENTS FOR MR IMAGING Ernest Groman, Lee Josephson, assigned to Advanced Magnetics
Jerome Lewis Incorporated
This invention relates to materials exhibiting certain magnetic and biological properties which make them uniquely suitable for use as magnetic resonance imaging (MRI) agents to enhance MR images of animal organs and tissues. More particularly, the invention relates to the in vivo use of biologically degradable and metabolizable superparamagnetic metal oxides as MR contrast agents. Depending on their preparation, these metal oxides are in the form of superparamagnetic particle dispersoids or superparamagnetic fluids where the suspending medium is a physiologically-acceptable carrier, and may be uncoated or surrounded by a polymeric coating to which biological molecules can be attached. These materials are administered to animals, including humans, by a variety of routes and the metal oxides therein collect in specific target organs to be imaged; in the case of coated particles, the biological molecules can be chosen to target specific organs or tissues. The biodistribution of the metal oxides in target organs or tissues results in a more detailed image of such organs or tissues because the metal oxides, due to their superparamagnetic properties, exert profound effects on the hydrogen nuclei responsible for the MR image. In addition, the dispersoids and fluids are quite stable and, in the case of the fluids, can even be subjected to autoclaving without impairing their utility. Furthermore, the materials are biodegradable and, in the case of iron oxide compounds, can eventually be incorporated into the subject’s hemoglobin, making them useful in treating anemia. Thus, the materials are well-suited for in vivo use.
A multiecho NMR pulse sequence is modified such that the bandwidth of the encoded NMR echo signal is reduced for the second NMR echo signal. This reduction is achieved by reducing the magnitude of the read-out magnetic field gradient, increasing the duration of the acquisition by a proportional amount and decreasing the sample rate by a proportional amount for the second NMR echo signal.
4952877 RF SYNTHESIZER OR AN NMR INSTRUMENT Robert S Stormont, Jeffrey P Noonan, Norbert Pelt assigned to General Electric Company The transceiver of an NRM instrument includes a digital synthesizer that produces an analog carrier signal which can be controlled in both frequency and phase and which can be frequency and phase modulated. The analog carrier signal is mixed with reference signals to boost its frequency to the Larmor frequency of the instrument.
4952878 MAGNETIC RESONANCE APPARATUS HAVING AN IMPROVED RF COIL Wilhelmus R M Mens, Peter H Wardenier, Eindhoven, Netherlands assigned to U S Philips Corporation An r.f. transmitter coil is coupled to individually or group-wise independently drivable antenna wire elements, each independently drivable element being driven by its own power amplifier via a sliding contact. An r.f. supply source is coupled to the inputs of the power amplifiers via an input network which provides a phase distribution among the r.f. signals supplied to the amplifiers for the coil to transmit with a circularly polarized r.f. field.
4952879 4952876 VARIABLE MULTIECHO Norbert J Pelt Company
BANDWIDTH NMR IMAGING
assigned
to General
Electric
MAGNETIC RESONANCE APPARATUS WITH UNCOUPLED RF COILS Johannes J Van Vaals, Anthonie Bergman, Eindhoven, Netherlands assigned to U S Philips Corporation